For Harry, it could be a huge blow. Hermione has always been his closest friend and advisor. Without her in the Order, Harry might feel lost and less confident in his decisions. He may start to question his own actions more, as Hermione was often the one to provide rational thinking.
The Order as a whole would be weakened. Hermione is a very intelligent and resourceful witch. Her skills in magic research and strategic planning are valuable assets. Without her, the Order may struggle to come up with effective plans against their enemies, and there could be a general sense of demoralization among the remaining members.
Well, it can change the whole dynamic of the story. For instance, if Hermione was a key part of a group in the fanfiction, her leaving might cause the group to fall apart or have to re - form in some way. The other characters will have to adjust to her absence, and new relationships and power dynamics may emerge.
The village elders would be in a state of panic. Naruto was seen as a symbol of hope and power for the village. His departure would mean a significant loss of strength and morale. The younger generation of ninja who looked up to Naruto would also be greatly affected. They might lose their motivation and start to question the values of the village.
Their relationship with Ron might be strained. Ron could feel abandoned and betrayed as he is left behind. He might initially be angry with them for leaving without him, but later come to understand their reasons.
For his friends, it could be a shock. They might feel abandoned and try to find him. Hermione, for example, would probably be worried sick and start looking for clues as to where he went. Ron might be more confused and angry at first, but then realize he needs to help find Harry. His family members would be devastated. His parents (if they are alive in the fanfiction) would be heartbroken, and his siblings might feel guilty or responsible.
In the fanfiction, Hermione could develop her character by learning to trust her instincts more. Working with the Order of Phoenix exposes her to many dangerous and uncertain situations. Through these experiences, she realizes that her gut feelings are often right and starts to rely on them more, which is a big step in her character development. Also, she may become more empathetic as she gets to know the members of the Order better and understand their individual struggles.
In most fanfictions, the Order of Phoenix doesn't betray Hermione. The Order is generally depicted as a good organization fighting against the Dark forces. Hermione is often seen as an important ally, and they work together towards common goals.
For the other Gryffindor students, some might be afraid of Hermione. They've heard stories about Greyback and werewolves, and this could lead to a divide in the house. Some students would stand by Hermione, while others would keep their distance. The teachers would also have different reactions. Snape might be more critical, seeing it as a sign of Hermione's recklessness. But McGonagall would be more empathetic, trying to find ways to help Hermione manage her new situation. The Order of the Phoenix members would be concerned about Hermione being a potential target now. They might increase security around her, which would impact the overall secrecy and operations of the Order.
For Harry, it would be devastating. Hermione has been his rock, his intellectual equal. Without her, he would feel lost and incomplete. He might become more reckless in his fight against evil, as he no longer has her to rein him in.
It can make other characters view their relationship as very exclusive. For example, Ron might feel left out sometimes if Harry is constantly overprotective of Hermione. This can create some tension between Ron and Harry in the fanfiction.
The other Titans might feel betrayed. Since Robin is often seen as a leader or an important part of the team, his sudden departure can make them wonder if they did something wrong. They could also feel less confident in their ability to function as a team without him.